著者

松森 唯益

出版者

Institute of Industrial Science The University of Tokyo

雑誌

生産研究 (ISSN:0037105X)

巻号頁・発行日

vol.71, no.2, pp.169-172, 2019-03-01 (Released:2019-03-30)

参考文献数

21

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力学系の急激な変化の予兆を捉える指標はearly-warning signals(EWS)と呼ばれる.EWS は力学系の分岐理論に基づいて理論的に導かれる.本解説では,EWS と力学系の分岐の関係を通じてEWS の概念を紹介する.また,多変量の力学系で利用される共分散に基づくEWS の理論的背景について説明する.最後に,EWS 研究の展望について述べる.

著者

森安 竜大 松森 唯益 永岡 真

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.854, pp.17-00144-17-00144, 2017 (Released:2017-10-25)

参考文献数

26

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A topology optimization method is proposed for the design of shallow-flow channels based on quasi-three-dimensional flow models of laminar and turbulent flows. The models for laminar flow and turbulent flow are derived from the Navier-Stokes equations and the Reynolds-Averaged Navier-Stokes (RANS) equations, respectively, by integrating along the direction of channel thickness. The thickness is employed as the design variable in the topology optimization. The design variables are updated using a time-dependent diffusion equation with a design sensitivity which is calculated by a discrete adjoint approach. Numerical examples for minimizing dissipation energy or variance of flow velocity magnitude using the topology optimization demonstrates that the proposed method is capable of finding optimal solutions that satisfy the KKT conditions. In the former example, the design domain was clearly divided into domains where the thickness was either near the upper limit or near the lower limit. However, in the latter example, the thickness was at an intermediate level in almost the whole the design domain. The distribution of the thickness varied depending on the Reynolds number in both examples.